1 62 Veterinary Medicine. 



tends to spontaneous recovery in from 15 to 40 days. Sick, 

 Greve, Fauvet and Grognier have respectively seen the parasite 

 transferred from horse to ox through the stalls and mangers, but 

 we have no evidence that it will persist on the latter, and the 

 rarity of the affection in cattle that have come in contact with 

 mangy horses, implies that this sarcoptes finds in the ox an un- 

 suitable field. Placed on the skin of sheep and pigs it did not 

 produce even temporary irritation. On dog and cat it lived for 

 a few days only. On dead carcases the .sarcoptes become tor- 

 pid on the subsidence of animal heat, and show no tendency to 

 migrate after twelve hours. It would not be quite safe, however, 

 to put such torpid acari on the warm skin of the living soliped. 



Symptoms. There is incessant, intolerable and extending 

 itching and rubbing of some circumscribed part of the skin, most 

 commonly about the head, roots of mane or tail, the withers, or 

 the back. When these parts are scratched the horse inclines 

 himself toward the hand and moves his lips as if he were himself 

 nibbling the skin. When the affected part is closely examined it 

 is found to be covered with an eruption of fine conical papillae, 

 many of which have a hair in the centre. The hairs of the affected 

 part stand erect and bristly, and many drop off, or are rubbed 

 out or twisted, but in the centre of the patch may still be noted 

 one or more hairs tenaciously holding their place. This serves 

 to distinguish from the absolutely bare, round patches of ring- 

 worm. The bare spots are at first scurfy, but soon become cov- 

 ered with yellowish scabs. True primary vesicles are rarely de- 

 tected, but the constant rubbing and consequent inflammation 

 cause more and more exudation, which concretes in .scabs and 

 crusts. Or from the continued rubbing, scratching and biting 

 there are formed open sores, vesicles and pustules, and the sub- 

 cutaneous connective tissue may be infiltrated and thickened with 

 exudate, and the skin thrown into ridges by the contractions of 

 the pauniculus muscle. The intensity of the symptoms varies 

 much with the stage and extension of the attack. The symp- 

 toms may be slight and equivocal in the first fourteen days, 

 though exceptionally it makes great progress in this length of 

 time. In any case by the sixth week the disease has usually 

 made extensive ravages, and from this time on it advances with 

 extraordinary rapidity. Such cases are marked not only by the 



